This is a very distressed rubber sword used by Manu Bennett as Crixus in arena scenes.
Here is a sword used by Reuden de Jong as Theokoles. The auction listing says it's made of rigid foam. They apparently received four of them from the art department.
This is a set of trademark daggers used by Dustin Clare as Gannicus. They are made of rubber.
My favourite item from this week is this commemorative clay tile like the one used by Nick Tarabay in the episode "Revelations."